A new antioxidant compound from Capparis spinosa

Figures & data

Figure 1.  Extraction, fractionation and column chromatography separation of fruits of C. spinosa.

Table 1.  The DPPH• scavenging activities of the extracts and the phenolic acids isolated from C. spinosa^a.

Test materials	SC50
EE	> 1 mg·mL^−1
PF	> 1 mg·mL^−1
EF	0.321 ± 0.001 mg·mL^−1
AF	0.421 ± 0.001 mg·mL^−1
cappariside (1)	0.204 ± 0.002 mM
protocatechuic aldehyde (2)	0.007 ± 0.0 mM
E-butenedioic acid (3)	> 1 mM
ethyl 3,4-dihydroxybenzoate (4)	0.011 ± 0.0 mM
syringic acid (5)	0.044 ± 0.002 mM
5-hydroxymethylfurfural (6)	> 1 mM
5-hydroxymethyl furoic acid (7)	> 1 mM
2-furoic acid (8)	>1 mM
protocatechuic acid (9)	0.032 ± 0.0 mM
vanillic acid (10)	0.09 ± 0.001 mM
succinic acid (11)	> 1 mM
4-hydroxybenzoic acid (12)	0.35 ± 0.017 mM
α-tocopherol	0.026 ± 0.001 mM

^a EE, ethanol extract; PF, petroleum ether fraction; EF, ethyl acetate fraction; AF, aqueous fraction of fruits of C. spinosa, respectively. The SC₅₀ values of EE, PF, EF, and AF are expressed as mg dried material equivalents/mL. The SC₅₀ values of compounds 1–12 and α-tocopherol are expressed in mM.

Figure 2.  HMBC of cappariside.

Table 2.  ¹H- and ¹³C-NMR data for compound 1 (¹H = 500 MHz, ¹³C = 125 MHz, CD₃OD, δ in ppm and J in Hz)^a

C	δC	δH	HMBC
2	140.7	7.93 (1H, s)	146.1, 152.2, 170.6
3	146.1	—	—
4	152.2	—	—
5	143.2	—	—
CH3	14.8	2.31 (3H, s)	143.2, 152.2
COOH	170.6	—	—

All the signals were assigned by 1D- and 2D-NMR.

^aAssignments are based on HSQC and HSBC.